I have a tuned pipe, great power but too noisy. Am going to leave that bike alone. The other bike has pretty much a standard exhaust. Today I replaced it with a larger tube & matched port. On the end of the tube I have two standaed HT mufflers IN PARRALLEL NOT IN SERIES. My thinking is that back pressure will be reduced but noise will not increase. Won't get to try it till the snow goes, what do you think the effect will be?